Promising Advances in Curative Therapies for Sickle Cell Disease

It’s not often that curative therapies come along for disorders affecting over 100,000 people in the United States alone—much less for common inherited disorders. That’s one reason this morning’s plenary, “Advances in Curative Therapies for Sickle Cell Disease,” is so exciting.

Attendees will hear from Mark C. Walters, MD, chief of the hematology division at the University of California at San Francisco, who has spent his career treating and researching hemoglobin disorders and sickle cell disease specifically. Walters is at the forefront of diverse new therapies for sickle cell disease, including lentiviral and homology-directed repair mechanisms.

He’ll explain how these techniques work as well as their pitfalls, describing his research and critical issues in the field that he and others are tackling. And importantly for laboratory professionals, he’ll discuss various assays tailored to support these new therapies for patients with sickle cell disease.

Even though more people worldwide suffer with sickle cell disease than with cystic fibrosis or hemophilia, sickle cell disease has historically received a fraction of the research funding that either of those disorders receive.

Now, however, after decades of stagnation—until 2017, there were only three approved sickle cell disease treatments—several new therapies were approved in just the last six years. And, very excitingly, new curative therapies are currently in trials.

Previously, only one “curative” sickle cell disease therapy existed: allogenic bone marrow transplants (BMT) from suitable donors. But such transplants are very difficult to access. For one reason, there are a limited number of suitable doners. Familial donors must not have any sickle genes to be eligible, and many families of sickle cell disease patients carry the genes in many if not most members. Additionally, BMT requires long-term immunosuppression, which comes with its own bevy of risks and costs, even as the therapy reduces the risks and costs of the disease itself.

Enter the availability of new and highly effective gene-editing tools. While these are not currently widely accessible, they carry a huge number of advantages over BMT. Not the least of these is the possibility for avoiding long-term immunosuppression. Walters has worked on several of these new therapies and is enthusiastic about the development of additional methods.

When asked why multiple treatments are necessary, Dr. Walters emphasizes that more methods mean more accessibility. “Differing treatment costs and time commitments would allow for greater flexibility based on patients’ needs and preferences. Moreover, some techniques may have cross-target issues that are problematic for certain patients based on their genes. This could be avoided with different techniques. After all, sickle cell disease affects many people in many ways—so we shouldn’t settle for a single treatment.”